There are numerous hydraulically or pneumatically actuated gate/door openers and closers. Hydraulically actuated openers and closers require motors, pumps and reservoirs, and are therefore relatively large. They require a significant amount of power for actuation and are therefore best suited to industrial applications.
For example, U.S. Pat. No. 4,416,085 discloses an automatic gate opening device where commercial electricity is not economically available, however, it requires a significant amount of power. A hydraulic cylinder operated by a motor and bidirectional gear pump moves a cylinder rod which connects to an opening rod. The opening rod is pivotally connected to one end to the gate and on the other end to a stationary location. Due to pivotal connections and a pivotal linkage near the middle of the opening rod, the gate may be opened and closed by the hydraulic cylinder. The hydraulic cylinder is also pivotally mounted. Electronic controls may be operated by a number of different type sensors, including limit switches on the hydraulic cylinder, sensors for detecting the gate location, manual switches or other traditional vehicle approach sensors. Power is provided by a storage battery, which battery can be recharged during daylight hours at a solar panel or by a traditional battery charger. The system is electrically driven. As the bidirectional pump is driven by a motor, this system requires a significant amount of power to operate. Further, in order for the hydraulic ram to effectively actuate opening and closing of the gate, a long opening rod is required, that includes a pivot linkage. This opening rod could easily be damaged as it is obtrusive. Although there is a timing circuit, it does not appear to be able to adjust the rate of opening and closing.
With regard to pneumatic actuators, U.S. Pat. No. 6,256,928 discloses an automated gate assembly, includes (i) a post; (ii) a gate pivotally coupled to the post, the gate pivoting between an open position and a closed position; and (iii) a gate opening assembly coupled to the gate. The gate opening assembly includes: (i) a pivoting assembly which selectively and simultaneously moves in both a linear and arcuate direction; and (ii) a connector connecting the pivoting assembly to the gate whereby actuation of the pivoting assembly rotates the gate from the open position to the closed position. The automatic gate assembly is particularly advantageous for mounting an automatic gate opening assembly on one side of a square or rectangular post while the gate is pivotally mounted on an adjacent side. A connector is able to readily clear the corner between the adjacent sides of the posts because of the unique configuration of the opening assembly. Any type of linear actuator, including a pneumatic actuator is contemplated. The assembly has at least one motor and hence requires a significant amount of power in order to function. Again, a long opening rod is required, that includes a pivot linkage. This opening rod could easily be damaged as it is obtrusive. This system has no provisions for adjusting the rate of opening and closing.
U.S. Pat. No. 5,050,344 discloses an automatic gate opening device which simultaneously lifts and opens the gate. A drive mechanism forces the gate upward, while a roller bearing following a helical slot in a tube causes rotation of the gate. Hinges are provided which allow simultaneous rotational and linear displacement of the gate. A pneumatic actuator is used. This requires an air compressor and the associated power in order to function, hence is not suitable for off the grid applications. This design is subject to malfunctioning if dirt or debris enter the helical slot. A timer is included in the control mechanism to control the amount of time that the air compressor is active.
U.S. Pat. No. 4,638,597 discloses a modular gate opening apparatus comprising a mounting frame which can be used to buttress a deteriorated fence post or secured to a new fence post. A vertical portion of the frame comprises a plurality of apertures in axial alignment allowing a wide variety of fastening means to be used to secure the frame in a number of configurations. A gate-receiving bracket is hingedly secured to the frame and is adapted to accommodate a wide variety of gate sizes. Actuator means are provided to move the gate receiving bracket, and the gate carried thereon, between an open and a closed position. The gate opening apparatus is electrically powered. In the preferred embodiment, an electric motor with a screw jack is used to actuate the opening apparatus. This requires a significant amount of power and is therefore not suited to off the grid applications. The opening apparatus includes a long opening rod that includes a pivot linkage. This opening rod could easily be damaged as it is obtrusive. The rate of opening and closing cannot be adjusted.
Various other types of gate or door opening devices have been designed in the past to utilize pneumatic cylinders and a mechanical linkage. U.S. Pat. No. 3,936,977 discloses a double acting power cylinder. A pivotal interconnecting linkage is utilized to open a door in response to the movement of a piston within the cylinder. It utilizes an air supply employed in commercial establishments, which is clearly an electrically powered compressor, as it is stated “The air supply system preferably is provided with a suitable manually operable power release valve unit 85 such that in the event of any malfunction, associated with, for example, a loss of electrical power, the power cylinder 9 can be completely exhausted.” This is therefore not suited to off the grid applications. Further, it is relatively complex.
Other types of gate opening devices have utilized a ram such as that shown in U.S. Pat. No. 3,500,585. An electric motor drives the ram. Further examples of gate opening devices are shown in U.S. Pat. Nos. 3,645,042, 2,592,891 and 4,231,190. U.S. Pat. No. 3,645,042 discloses a pneumatically actuated opener and spring closure for a door. U.S. Pat. No. 2,592,891 discloses an electric motor driven opener. U.S. Pat. No. 4,231,190 discloses a chain drive opener that is remotely controlled.
A pneumatic catch mechanism is disclosed in U.S. Pat. No. 6,408,571. More specifically, it discloses an automatic closing gate having a gate post and at least one self-closing hinge attaching the gate to the gate post. A catch post having a catch holds the gate in an open position for a period of time. The catch releases the gate after the period of time and the gate is free to swing shut. The catch is manually engaged and pneumatically released. The time that the gate is open is controlled by the rate of travel of the piston. The gate is self-closing so there is no control of the speed of closing. Further, the gate must be opened manually.
What is needed is a gate opener and closer coupled to a latch opener that can be operated with a source of compressed gas and an electrical source for powering the opening and closing of valves, and solenoid valves. The compressed gas would be provided as a canister as opposed to a compressor or other apparatus requiring an electrical, solar, gas or diesel input. Preferably, the source of compressed gas is a carbon dioxide canister. This would allow for the opener, closer and latch opener to operate off the grid and without additional equipment. It would be advantageous if the system could be used for the opening and closing of large gates, such as those in industrial, farm and ranch settings. It would be a further advantage if the actuator inherently provided a safety stop. It would be of further advantage if the rate of opening and closing could be optimized for the location and user requirements.